The invention concerns a mechanical gripping device for rotating jaw chucks or collet chucks whereby the rotationally symmetrical parts can be gripped from the outside or from the inside with the help of prestressed springs arranged in a bore hole of a spindle. The springs can be prestressed by means of axial displacement of a pull rod or pressing rod which is connected with the jaw chuck or respectively the collet chuck. With some known mechanical gripping devices of this kind, rotationally symmetrical parts in a rotating jaw chuck or a rotating collet chuck can either be gripped only from the outside or only from the inside. Furthermore, gripping devices are known for machine tools which activate pneumatically, hydraulically or electromagnetically rotating jaw chucks and collet chucks.
In addition, mechanical gripping devices are known (See "Machinery", Vol. 87, pages 1308-1039, Dec. 2, 1955; German Pat. No. 597,678; and Great Britain Pat. No. 416,153, all incorporated herein by reference) wherein a gripping of rotationally symmetrical parts is possible both from the outside and from the inside.
In the case of such known devices, in a bore hole of the spindle, a jacket or socket 37 (as shown in the above indicated British Patent drawings) is arranged shiftably in which springs 39, 41 act upon a helical spring plate 38. This helical spring plate is tightly connected with the centrally arranged slide 31 whose free end is connected with a jaw chuck or, respectively, with a collet chuck.